Merge 2 arrays with no duplicated keys

Question

I have 2 arrays like below and want to merge them together and not duplicate keys into a new array.

$array1:

Array
(
[0] => Array
    (
        [a] =&         


        

Answer 1

function array_merge_recursive_unique($array1, $array2) {
  if (empty($array1)) return $array2; //optimize the base case

  foreach ($array2 as $key => $value) {
    if (is_array($value) && is_array(@$array1[$key])) {
      $value = array_merge_recursive_unique($array1[$key], $value);
    }
    $array1[$key] = $value;
  }
  return $array1;
}